1. Field of the Invention
The present invention relates to an apparatus for X-ray treatment and a treatment method using the apparatus. More particularly, the present invention relates to an apparatus and a method which can prevent the destruction of normal tissue with a new technique called MMRT (Microbeam Modulated Radiation Therapy).
2. Description of the Related Art
Disadvantageously, X-rays in an X-ray treatment are radiated to any normal tissue other than a lesion because the X-rays are radiated to the lesion through the normal tissue and the lesion moves by the breathing and other motion of the patient also. Various kinds of measures are effected for this problem.
Japanese Patent No. 3,790,481 discloses a radiation treatment apparatus which comprises a radiation generator radiating X-rays for treatment, two radiation sources irradiating X-rays for inspecting, two or more detectors, an image forming apparatus, and an analyzer. In the radiation treatment apparatus, the aperture shape of the collimator is adjusted according to calculations of the three-dimensional position and shape of the targets object part from the three-dimensional image of the inspection object part. The apparatus tracks the radiation field for treatment corresponding to the treatment object part. The apparatus cannot radiate the X-ray until the setting of the aperture shape of the collimator is completed because it tracks the moving treatment object part by changing the aperture shape of the collimator. In this apparatus, because the geometric accuracy of the radiation field depends on the setting accuracy of the aperture shape of the collimator, it is difficult to realize both rapidity and high resolution together.
Japanese Patent No. 3,881,199 discloses a radiation treatment apparatus and radiodiagnosis apparatus which can efficiently treat and diagnose with a radiation generator which can lead the breathing of the patient to be easy to take the timing and synchronization of the radiation. However, the apparatus cannot track the moving treatment object part in real time.
Japanese Patent No. 3,748,531 discloses a radiation therapy apparatus which can reduce the exposure dose to normal tissues by irradiating a tumor in the soma selectively with a large dosage. In the patent, three tumor markers embedded in the vicinity of the tumor are captured by fluoroscope from two directions. The captured two-dimensional transillumination images are digitized, and template matching is performed using the gray-level normalization cross correlation method between the digitized images and the template images of the tumor markers registered beforehand for the predetermined frame in real time to calculate the two-dimensional coordinates of the three tumor markers with a higher correlation degree on the digitized fluoroscopy images. The position of the isocenter and the three-dimensional coordinates of the three tumor markers at least are calculated based on the calculated two-dimensional coordinates of the three tumor markers, compensating for the difference from the position of isocenter in the original planning. However, it is difficult to improve the rapidity any further in this radiation therapy apparatus, because the rapidity of the continuous radiation is limited by the place recognition of the tumor markers and the settling time of the collimator. Even more particularly, in the case of radiation to the edge part of the tumor, it is difficult to avoid the normal tissues because the collimator is used, and normal tissues are damaged.
Japanese Patent No. 3,053,389 discloses a moving body tracking irradiating apparatus which is composed of a first X-ray fluoroscope, a second X-ray fluoroscope, a first and a second recognition processing section, a central arithmetic processing section, and an irradiating control section. The first X-ray fluoroscope captures the images of a tumor marker embedded in the vicinity of the tumor from a first direction, and the second X-ray fluoroscope captures the images of the tumor marker from a second direction, and the captured two-dimensional transillumination images are digitized. The first and second recognition processing sections calculate the first and the second two-dimensional coordinates of the tumor marker using the gray-level normalization cross correlation method. The central arithmetic processing section calculates the three-dimensional coordinate of the tumor marker from two-dimensional coordinates calculated by the first and second recognition processing sections. The irradiating control section controls the radiation of the treatment beam from a LINAC based on the three-dimensional coordinates of the tumor marker. Thus this apparatus can reduce the exposure dose to normal tissues by irradiating selectively to the moving tumor in the soma with a large dosage. However, it is difficult to improve the rapidity any further in this radiation therapy apparatus, because the rapidity of the continuous radiation is limited by the position recognition of the tumor markers and the settling time of the collimator. Even more particularly, in the case of radiation to the edge part of the tumor, it is difficult to avoid normal tissues because the collimator is used, and normal tissues are damaged.
Japanese Unexamined Patent Application Publication No. 2003-523220 (U.S. Pat. No. 6,144,875) discloses an apparatus and method for performing treatment on an internal target region while compensating for breathing and other motion of the patient. The apparatus comprises a first imaging device for periodically generating positional data about the internal target region and a second imaging device for continuously generating position data about one or more external markers adapted to be attached to the patient's body or any external sensor. The apparatus further comprises a processor that receives the positional data about the internal target region and the external markers in order to generate a correspondence between the position of the internal target region and the external markers and a treatment apparatus that directs the treatment towards the position of the target region of the patient based on the positional data of the external markers. However, it is difficult to improve the rapidity any further in this radiation therapy apparatus, because the rapidity of the continuous radiation is limited by the position recognition of the tumor markers and the settling time of the collimator. Even more particularly, in the case of radiation to the edge part of the tumor, it is difficult to avoid normal tissues because the collimator is used, and normal tissues are damaged.
Each previously described apparatus includes the following problems. The patient's mental and physical burdens are heavy because it is not possible to irradiate continuously and it takes time for the treatment. The accuracy of verification of the consequences of the X-ray treatment is inferior and complicated. Because the diameter of the X-ray beam cannot be thin, it is difficult to completely remove tumors without damaging normal tissue. As for the radiation direction of the apparatus, the gantry type cannot irradiate the tumor from any direction and the optimum angle.
It is an object of the present invention to provide the X-ray treatment apparatus which can track the moving tumor in real time, and can perform rapidly X-ray treatment along the shape of the object tumor with high accuracy without damage to the normal tissues by the high power and thin X-ray beam.